The multiple pixel avalanche photo detector device commonly called MPPC or SiPM device is a relative newcomer to the field of radiation detection instrumentation but is being increasingly employed as a photo-detection element in critical systems where the gain stabilization is important.
The SiPM exhibits a temperature dependence of gain that is very nearly linear with temperature. Because photodetector gain impacts the ability to perform spectrometric measurements, and influences the timing and energy precision of threshold discrimination circuits—both techniques important in nuclear measurements and particularly in quantitative studies—it is often essential to stabilize the gain of the device with respect to temperature.
Previous approaches to stabilization have included active temperature measurement and control via either varying the applied biasing voltage, by control of a variable gain stage following the signal output of the SiPM, or by means of a look up table that corrects for gain variation after digitization. Where power consumption and cost are not a major concern these approaches are often the appropriate method. If the cost, size or power consumption of the gain stabilization scheme is important, as it is in large arrays of these devices, a low power and small area approach is highly desirable and in some cases can be the only practical approach.